CN212391107U - Distributed optical fiber sensing detection system - Google Patents
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- CN212391107U CN212391107U CN202021656507.XU CN202021656507U CN212391107U CN 212391107 U CN212391107 U CN 212391107U CN 202021656507 U CN202021656507 U CN 202021656507U CN 212391107 U CN212391107 U CN 212391107U
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 46
- 238000001514 detection method Methods 0.000 title claims abstract description 40
- 238000001069 Raman spectroscopy Methods 0.000 claims abstract description 24
- 238000006243 chemical reaction Methods 0.000 claims abstract description 8
- 239000000835 fiber Substances 0.000 claims abstract description 7
- 230000003287 optical effect Effects 0.000 claims description 67
- 238000012544 monitoring process Methods 0.000 description 3
- 230000001427 coherent effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 230000001360 synchronised effect Effects 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
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- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
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Abstract
The utility model discloses a distributed optical fiber sensing detection system, which comprises a light source output unit, a circulator and optical fibers which are connected in sequence, wherein the circulator is also connected with a photoelectric detection unit, an A/D conversion unit, a data acquisition unit and an upper computer in sequence; the utility model discloses when using, the detection light of light source output unit output excites rayleigh scattered light, raman scattered light and brillouin scattered light behind circulator and optic fibre in optic fibre, rayleigh scattered light, raman scattered light and brillouin scattered light return to in the circulator and go into the photoelectric detection unit, later transmit to the host computer through AD converting unit, data acquisition unit to return to in the light source output unit, realize that the three parameter of vibration, temperature, strain is measured simultaneously.
Description
Technical Field
The utility model belongs to the technical field of the optical fiber sensing, concretely relates to distributing type optical fiber sensing detecting system.
Background
The distributed optical fiber sensor has many advantages of long-distance distributed measurement, electromagnetic interference resistance, corrosion resistance, electrical insulation and the like, and is widely applied to the fields of railway/subway communication cables, subway rails, tunnels and the like which need long-distance vibration temperature and strain detection.
The following are widely used at present: the distributed optical fiber sensor based on Rayleigh scattering detects vibration, the distributed optical fiber sensor based on Raman scattering detects temperature, and the distributed optical fiber sensor based on Brillouin scattering detects temperature/strain; in the traditional technology, Rayleigh scattering, Raman scattering and Brillouin scattering can be realized on only one sensor, and are relatively single.
SUMMERY OF THE UTILITY MODEL
In order to solve the problem, the utility model provides a distributed optical fiber sensing detecting system through carrying out synchronous integration to rayleigh scattering, raman scattering and brillouin scattering, can realize the synchronous detection of same distributed optical fiber sensor to vibration, temperature and meeting an emergency.
The utility model adopts the technical proposal that:
a distributed optical fiber sensing detection system comprises a light source output unit, a circulator and optical fibers which are sequentially connected, wherein the circulator is further sequentially connected with a photoelectric detection unit, an A/D conversion unit, a data acquisition unit and an upper computer;
after the detection light output by the light source output unit passes through the circulator and the optical fiber, Rayleigh scattering light, Raman scattering light and Brillouin scattering light are excited in the optical fiber, return to the circulator and enter the photoelectric detection unit, then are transmitted to the upper computer through the A/D conversion unit and the data acquisition unit, and return to the light source output unit to trigger signals to continue to send laser.
Preferably, the photodetection unit includes an optical filter, a wavelength division multiplexer, a first photodetector, a second photodetector, a third photodetector, a fourth photodetector, and a decoupling module, an input end of the optical filter is connected to the circulator, an output end of the optical filter is connected to the wavelength division multiplexer and the first photodetector, the wavelength division multiplexer is connected to the second photodetector, the third photodetector, and the fourth photodetector, and the first photodetector, the second photodetector, the third photodetector, and the fourth photodetector are all connected to the decoupling module;
the Rayleigh scattered light enters the first photoelectric detector, simultaneously, Stokes light and anti-Stokes light in the Raman scattered light respectively enter the third photoelectric detector and the fourth photoelectric detector, and Brillouin scattered light enters the second photoelectric detector.
Preferably, the light source output unit includes a laser, an optical coupler, a pulse optical modulator, and an optical amplifier, the laser, the optical coupler, the pulse optical modulator, and the optical amplifier are connected in sequence, and the optical amplifier is connected to the circulator.
Preferably, the optical fiber sensing detection system further comprises an optical frequency shifter and an optical polarizer, wherein the input end of the optical frequency shifter is connected with the optical coupler, the output end of the optical frequency shifter is connected with the optical polarizer, and the optical polarizer is connected with the second photoelectric detector.
Preferably, the first photodetector, the second photodetector, the third photodetector and the fourth photodetector are all APD photodetectors.
Preferably, the circulator is a three-terminal circulator.
Preferably, the optical frequency shifter is an electro-optical modulator.
Preferably, the optical frequency shifter is an acousto-optic modulator.
Compared with the prior art, the utility model discloses when using, behind light source output unit's the detection light circulator and optic fibre, arouse rayleigh scattered light, raman scattering light and brillouin scattered light in the optic fibre, rayleigh scattered light, raman scattering light and brillouin scattered light return to in the circulator and go into the photoelectric detection unit in, later transmit to the host computer through AD converting unit, data acquisition unit to return to in the light source output unit, realize that the three parameter of vibration, temperature, strain is measured simultaneously.
Drawings
Fig. 1 is a system block diagram of a distributed optical fiber sensing detection system according to an embodiment of the present invention.
Wherein:
1. the optical fiber coupling device comprises a light source output unit, 2. a circulator, 3. an optical fiber, 4. a photoelectric detection unit, 5. an A/D conversion unit, 6. a data acquisition unit, 7. an upper computer, 8. an optical frequency shifter, 9. an optical polarizer, 11. a laser, 12. an optical coupler, 13. a pulse optical modulator, 14. an optical amplifier, 41. an optical filter, 42. a wavelength division multiplexer, 43. a first photoelectric detector, 44. a second photoelectric detector, 45. a third photoelectric detector, 46. a fourth photoelectric detector and 47. a decoupling module.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the description of the present invention, it should be clear that the terms "vertical", "horizontal", "longitudinal", "front", "rear", "left", "right", "up", "down", "horizontal", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description of the present invention, and do not mean that the device or element referred to must have a specific orientation or position, and thus, cannot be construed as limiting the present invention.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The embodiment of the utility model provides a distributed optical fiber sensing detection system, as shown in fig. 1, it includes light source output unit 1, circulator 2 and optic fibre 3 that connect gradually, circulator 2 still is connected with photoelectric detection unit 4, AD converting unit 5, data acquisition unit 6 and host computer 7 in proper order;
thus, with the above configuration, the detection light output by the light source output unit 1 passes through the circulator 2 and the optical fiber 3, and then the rayleigh scattered light, the raman scattered light, and the brillouin scattered light are excited in the optical fiber 3, and then return to the circulator 2 and enter the photodetection unit 4, and then pass through the a/D conversion unit 5 and the data acquisition unit 6 to the upper computer 7, and return to the light source output unit 1 to trigger the signal to continue to transmit the laser light.
Specifically, the photodetection unit 4 includes an optical filter 41, a wavelength division multiplexer 42, a first photodetector 43, a second photodetector 44, a third photodetector 45, a fourth photodetector 46, and a decoupling module 47, an input end of the optical filter 41 is connected to the circulator 2, an output end is connected to the wavelength division multiplexer 42 and the first photodetector 43, the wavelength division multiplexer 42 is connected to the second photodetector 44, the third photodetector 45, and the fourth photodetector 46, and the first photodetector 43, the second photodetector 44, the third photodetector 45, and the fourth photodetector 46 are all connected to the decoupling module 47;
the rayleigh scattered light enters the first photodetector 43, while stokes light and anti-stokes light in the raman scattered light enter the third photodetector 45 and the fourth photodetector 46, respectively, and brillouin scattered light enters the second photodetector 44.
Specifically, one end of the circulator 2 is input to the optical filter 41 and then divided into two paths, one path is rayleigh scattered light and directly enters the first photodetector 43, the other path enters the wavelength division multiplexer 42 and then is divided into three paths and respectively enters the three photodetectors, brillouin scattered light directly enters the second photodetector 44, and stokes light and anti-stokes light in the raman scattered light respectively enter the third photodetector 45 and the fourth photodetector 46.
The light source output unit 1 comprises a laser 11, an optical coupler 12, a pulse light modulator 13 and an optical amplifier 14, wherein the laser 11, the optical coupler 12, the pulse light modulator 13 and the optical amplifier 14 are sequentially connected, and the optical amplifier 14 is connected with the circulator 2;
the line width of the light source emitted by the laser 11 should be smaller than the Brillouin scattering line width;
in the distributed optical fiber based on the brillouin scattering, generally, lasers are narrow linewidth light sources, and if the linewidth of the light source is larger than the brillouin linewidth, the brillouin scattering phenomenon is not easy to occur.
Thus, the pulse light sequence generated by the pulse light modulator 13 enters the optical fiber 3 through the optical amplifier 14, the scattered light returned from the optical fiber 3 is transmitted to the optical filter 41 through the circulator and then is divided into two paths, one path of rayleigh scattered light passes through the first photodetector 43, and the other path of rayleigh scattered light passes through the wavelength division multiplexer 42 and is divided into three paths, namely brillouin scattered light, raman anti-stokes scattered light and raman stokes scattered light;
the scattered light is converted into an electric signal by an optical signal after being subjected to photoelectric detection, the electric signal is subjected to A/D conversion after passing through the decoupling module 47, data is acquired and transmitted to the upper computer, and the upper computer triggers the pulse light modulator again after receiving data information to carry out vibration, temperature and strain information detection again.
The optical fiber sensing detection system further comprises an optical frequency shifter 8 and an optical polarizer 9, wherein the input end of the optical frequency shifter 8 is connected with the optical coupler 12, the output end of the optical frequency shifter 8 is connected with the optical polarizer 9, and the optical polarizer 9 is connected with the second photoelectric detector 44;
thus, the light polarizer 9 controls the polarization of the frequency-shifted light to obtain a desired polarized light, controls the polarization direction of the light, and can also attenuate the light intensity of the light.
The first photodetector 43, the second photodetector 44, the third photodetector 45 and the fourth photodetector 46 are all APD photodetectors;
thus, the APD photoelectric detector can realize photoelectric detection of three types of scattering, namely Rayleigh scattering light, Raman scattering light and Brillouin scattering light.
The circulator 2 is a three-terminal circulator.
In one embodiment, the optical frequency shifter 8 is an electro-optical modulator;
in another embodiment, the optical frequency shifter 8 is an acousto-optic modulator;
in this way, the input optical signal is subjected to a certain optical frequency shift by modulation, and the optical signal is output to the photodetector to be subjected to coherent demodulation with the brillouin scattered light signal, or direct photoelectric detection may be employed.
In addition, the optical fiber 3 is a long-distance sensing optical fiber.
The working principle is as follows:
the detection light output by the light source output unit 1 is connected with the wavelength division multiplexer 42, the first photodetector 43 and the long-distance sensing optical fiber 3 through the three-port circulator 2, and rayleigh scattering light, raman scattering light and brillouin scattering light are respectively excited in the long-distance sensing optical fiber 3, wherein the rayleigh scattering light returns to the three-port circulator 2 and enters the first photodetector 43 from the transceiving multiplexing end of the three-port circulator 2, meanwhile, stokes light and anti-stokes light in the raman scattering light enter the third photodetector 45 and the fourth photodetector 46 respectively, and the brillouin scattering light enters the second photodetector 44;
for temperature monitoring: when the external temperature changes and acts on the long-distance sensing optical fiber 3, the Raman scattering light intensity in the optical pulse width range is caused to change, so that the light intensity of the anti-Stokes light in Raman scattering is caused to change, the temperature information carried in the anti-Stokes light can be demodulated by taking the Stokes light as reference light, and the position information of the temperature change can be obtained by performing accumulation average processing on the signals acquired in a plurality of sampling periods;
for vibration monitoring: when external vibration is applied to the long-distance sensing optical fiber 3, the phase of backward Rayleigh scattering light in the optical pulse width range is changed, the light intensity of the backward Rayleigh scattering light is further changed, moving average processing is carried out on a large number of signals acquired in a plurality of sampling periods, vibration position information can be obtained, time domain signals of vibration positions are taken out, non-uniform Fourier transform is carried out on the time domain signals, and vibration frequency information can be obtained;
for strain monitoring, the spectrum of spontaneous Brillouin scattering light of a backward optical fiber is used for measuring the strain of the optical fiber.
In the embodiment, the distributed optical fiber sensing of Brillouin scattering, Raman scattering and Rayleigh scattering is realized in the same optical fiber sensor; simultaneously, the temperature compensation is carried out on the Brillouin scattering by utilizing the Raman scattering, and the simultaneous measurement of the vibration, the temperature and the strain is realized by combining the Rayleigh scattering; and by utilizing pulse modulation and optical coherent detection technologies, the detection signal-to-noise ratio is improved, the sensing distance is prolonged, and the detection precision is improved.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. A distributed optical fiber sensing detection system is characterized by comprising a light source output unit (1), a circulator (2) and an optical fiber (3) which are sequentially connected, wherein the circulator (2) is further sequentially connected with a photoelectric detection unit (4), an A/D conversion unit (5), a data acquisition unit (6) and an upper computer (7);
after detected light output by the light source output unit (1) passes through the circulator (2) and the optical fiber (3), Rayleigh scattered light, Raman scattered light and Brillouin scattered light are excited in the optical fiber (3), the Rayleigh scattered light, the Raman scattered light and the Brillouin scattered light return to the circulator (2) and enter the photoelectric detection unit (4), and then are transmitted to the upper computer (7) through the A/D conversion unit (5) and the data acquisition unit (6), and return to the light source output unit (1) to trigger signals to continue to send laser.
2. The distributed optical fiber sensing detection system of claim 1, the photoelectric detection unit (4) comprises an optical filter (41), a wavelength division multiplexer (42), a first photoelectric detector (43), a second photoelectric detector (44), a third photoelectric detector (45), a fourth photoelectric detector (46) and a decoupling module (47), the input end of the optical filter (41) is connected with the circulator (2), the output end is connected with the wavelength division multiplexer (42) and the first photoelectric detector (43), the wavelength division multiplexer (42) is connected with a second photo detector (44), a third photo detector (45) and a fourth photo detector (46), the first photoelectric detector (43), the second photoelectric detector (44), the third photoelectric detector (45) and the fourth photoelectric detector (46) are all connected with a decoupling module (47);
the Rayleigh scattered light enters a first photodetector (43), simultaneously, Stokes light and anti-Stokes light in the Raman scattered light enter a third photodetector (45) and a fourth photodetector (46), respectively, and Brillouin scattered light enters a second photodetector (44).
3. A distributed optical fiber sensing detection system according to claim 2, wherein the light source output unit (1) includes a laser (11), an optical coupler (12), a pulsed light modulator (13) and an optical amplifier (14), the laser (11), the optical coupler (12), the pulsed light modulator (13) and the optical amplifier (14) are connected in sequence, and the optical amplifier (14) is connected with the circulator (2).
4. A distributed fibre optic sensing detection system according to claim 3 further comprising an optical frequency shifter (8) and an optical polarizer (9), the input of said optical frequency shifter (8) being connected to the optical coupler (12), the output of said optical frequency shifter (8) being connected to the optical polarizer (9), said optical polarizer (9) being connected to the second photodetector (44).
5.A distributed optical fiber sensing detection system according to any of claims 2-4, wherein the first photodetector (43), the second photodetector (44), the third photodetector (45) and the fourth photodetector (46) are all APD photodetectors.
6. A distributed fibre optic sensing detection system according to claim 1 wherein the circulator (2) is a three-terminal circulator.
7. A distributed optical fiber sensing detection system according to claim 4, wherein said optical frequency shifter (8) is an electro-optical modulator.
8. A distributed optical fiber sensing detection system according to claim 4, wherein said optical frequency shifter (8) is an acousto-optic modulator.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111780859A (en) * | 2020-08-11 | 2020-10-16 | 浙江长芯光电科技有限公司 | Distributed optical fiber sensing detection system |
| CN115388957A (en) * | 2022-10-26 | 2022-11-25 | 高勘(广州)技术有限公司 | Method, device and system for detecting OPGW optical cable icing and storage medium |
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2020
- 2020-08-11 CN CN202021656507.XU patent/CN212391107U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111780859A (en) * | 2020-08-11 | 2020-10-16 | 浙江长芯光电科技有限公司 | Distributed optical fiber sensing detection system |
| CN115388957A (en) * | 2022-10-26 | 2022-11-25 | 高勘(广州)技术有限公司 | Method, device and system for detecting OPGW optical cable icing and storage medium |
| CN115388957B (en) * | 2022-10-26 | 2023-01-31 | 高勘(广州)技术有限公司 | Method, device and system for detecting OPGW optical cable icing and storage medium |
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